The first adjustment came early, like in the opening huddle.
"It's weird because we're so used to hearing Lu say, 'Bulls on three' and then counting us out," guard Jimmy Butler said. "And it's not Lu anymore."
So who did it?
"Me," Butler said. "And it was weird. But, new roles, new leaders. Gotta step up."
It's not just the players. As Bulls coach Tom Thibodeau patrolled the home sideline during the Bulls' 92-87 win over Phoenix, huffing and puffing as if it were Game 7 of the NBA Finals, you could sense he was missing something, like a phantom security blanket.
I asked Thibs if he tried to put Deng in the game and he laughed. (Of course, I wouldn't have asked that if the Bulls had lost.)
For Thibs, it's always about the next game, an important attitude for a coach who tries to bend a team around his iron will.
But Deng's not coming off that bench. He's gone. And the Bulls have to figure out how to survive the rest of the season down one very important man and to replace an all-purpose wing who also was the locker room sage.
Thibodeau and the players are responsible for the present, ugly as it looks sometimes, while the front office has to plan for the future.
"Their job is to make financial decisions, to make player personnel decisions and things of that nature," Thibodeau said after the morning shootaround. "Their job is to do that. My job is to coach the guys that are here."
In that sense, with Deng gone, the pressure is off for the players to justify his presence in a contract year. We know the remaining Bulls will play hard and even the pro-tanking faction of Chicago has to like that, at least grudgingly.
The Bulls could still part with, say, Mike Dunleavy and Kirk Hinrich this season, but they would have to get something decent in return. I don't foresee any other rotation players leaving and new arrival D.J. Augustin looks like a keeper and a fine backup to Derrick Rose next season.
The Bulls need to have a Thibodeauan flair for living in the moment to move past the Deng era. Deng was a franchise icon and the ideal player to epitomize the culture change John Paxson wanted when he took over as the general manager in 2003.
Because of that, Deng will never be forgotten as long as his former teammates carry on his life's work of playing a lot of minutes for a demanding coach.
And here's the first thing you need to remember about the post-Luol era: The Bulls are not rebuilding. Not tanking, either. But definitely not rebuilding.
Then erase "rebuilding" from your Bulls vocabulary.
"Rebuilding is not a word to use when you still have players like Joakim Noah on your team and you still have Derrick Rose, who we fully expect to come back healthy," Paxson, now the Bulls vice president of basketball operations, said Tuesday in his media tour. "You don't rebuild with a coach like Tom."
Thibodeau's next-man-up philosophy was justified Tuesday evening as the Bulls beat Phoenix with an eight-man rotation. Noah and Taj Gibson combined for 33 points and 26 rebounds.
The Bulls will win games like this all season, and when guys go down -- Carlos Boozer was out Tuesday -- they will get drilled by teams both good and bad.
After this season ends, what comes next for the Bulls is the unknown. Like Noah leading the fast break, it's a little exciting and a little scary.
The Bulls aren't giving up or starting over. The core of Noah, Gibson, Butler and Rose isn't going anywhere. You build around those guys. How the Bulls surround them with more talent is the question.
Butler, one of the few core players sure to be around for the next run at a ring, said the current Bulls will use the obvious disrespect for this battered roster as their fuel. How long that will last with 49 games left is anyone's guess.
"This deal makes a lot of sense," Paxson said. "We believe it puts us in the position to be aggressive going forward when given the opportunity, and we will. The onus is on us. When you get financial flexibility, you have to use that in the right way. When you have draft picks, you have to make good basketball decisions."
With Deng, you had a known commodity. You knew exactly what he could do and how well he could it.
The Bulls have not done well with the unknown in the post-Jordan era.
A marching band to meet Tracy McGrady. A failed pitch in Cleveland to land LeBron James. These trips to the unknown turned into the likes of Ron Mercer and Eddie Robinson and the much better, but still disappointing, addition of Boozer.
While there is a solid core, Boozer is not part of it. Will Boozer get amnestied? That decision hasn't been made, but Paxson didn't shoot down the mention of it.
"Everybody knows we have the amnesty clause available to us," he said. "It's a decision that will be made but will not be made today. Let me say this about Carlos, I think Carlos sometimes gets unfair criticism. Think about the last three or four years: The one player who practiced every day, played almost every game, came with positive attitude, is Carlos Boozer."
Before that happens, the Bulls also need to sign another scoring guard to take pressure off Rose. Butler and sweet-shooting rookie Tony Snell look more like small forwards.
Grantland's NBA writer extraordinaire Zach Lowe mentioned Indiana's Lance Stephenson as a possibility Tuesday. That would be nice, if the Bulls can clear more salary for him. With Noah and Gibson, the team's personal ties to New York, the Bulls wouldn't even need Rose to recruit the Coney Island native.
It's still too early to project other additions for next season, but while the Bulls front office gets criticized for any number of reasons, they know how to add talent. Just ask the talent.
"I feel like they've done a great job of putting this team together," said Butler, who was drafted at the end of the first round in 2011. "I feel like they're going to do what's best for us in the long run. They've done a great job of drafting guys, putting high-character guys around each other who work and compete together as a team."
Rose was walking freely around the United Center on Tuesday morning and is expected to recover fully from his medial meniscus surgery. What happens to his game after that surgery is the Bulls' greatest unknown.
But what the Bulls do know is they can't just count on Rose in the near future. As Paxson said, the onus is on the front office to build a team for the present, and in a hurry. The Bulls brass showed seriousness about presenting a strong public front by sending a letter to season-ticket holders Tuesday afternoon.
"But the challenge always is building a team and putting the group of players together; in this case it might be more about building with Derrick, as opposed to saying, 'OK, Derrick, you got to shoulder all the burden,'" Paxson said. "But that's OK. Because I've seen plenty of teams win in this league, too, at a very high level, going about it that way."
Which way will the Bulls go? A great question for another time. I can't wait to see the answer.